UNITED STATES

SECURITIES AND EXCHANGE
COMMISSION

Washington, D.C. 20549

SCHEDULE 13D
(Rule 13d-101)

Item 5.

Interest in Securities of the Issuer

Item 5 is hereby amended as follows:

(a) OCM Principal Opportunities Fund II, L.P. (the “Principal Fund”) beneficially owns and has sole power to vote and dispose of 6,325,307 shares of the Issuer’s Common Stock (approximately 15.9% of the outstanding shares of the Issuer’s Common Stock), and OCM/GFI Power Opportunities Fund, L.P. (the “Power Fund” and, together with the Principal Fund, the “OCM Funds”) beneficially owns and has sole power to vote and dispose of 6,325,307 shares of the Issuer’s Common Stock (approximately 15.9% of the outstanding shares of the Issuer’s Common Stock).

As of the date of this Schedule 13D, Oaktree Capital Management, LLC (“Oaktree”), in its capacity as the general partner of the Principal Fund and the co-general partner of the Power Fund, may be deemed to beneficially own the 12,650,614 shares of Common Stock of the Issuer (approximately 31.8% of the outstanding shares of the Issuer’s Common Stock) held by the OCM Funds.  As of the date of this Schedule 13D, GFI Energy Ventures LLC (“GFI”), in its capacity as the co-general partner of the Power Fund, may be deemed to beneficially own the 6,325,307 shares of Common Stock of the Issuer (approximately 15.9% of the outstanding shares of the Issuer’s Common Stock) held by the Power Fund. 

(b) Oaktree has discretionary authority and control over all of the assets of the Principal Fund pursuant to its status as general partner of the Principal Fund, including the power to vote and dispose of the Issuer’s Common Stock.  In addition, Oaktree has shared discretionary authority and control over all of the assets of the Power Fund pursuant to its status as co-general partner of the Power Fund, including shared power to vote and dispose of the Issuer’s Common Stock. Therefore, Oaktree has sole power to vote and dispose of 6,325,307 shares of the Issuer’s Common Stock and shared power to vote and dispose of 6,325,307 shares of the Issuer’s Common Stock.

GFI has shared discretionary authority and control over all of the assets of the Power Fund pursuant to its status as co-general partner of the Power Fund, including shared power to vote and dispose of the Issuer’s Common Stock. Therefore, GFI has shared power to vote and dispose of 6,325,307 shares of the Issuer’s Common Stock.

Oaktree, GFI and each of the individuals listed in Item 2 to this Schedule 13D disclaims beneficial ownership of the shares of the Issuer’s Common Stock held by the OCM Funds, and the filing of this Statement 13D shall not be construed as an admission that any such person is the beneficial owner of any such securities.

(c) On March 24, 2006, the Principal Fund sold 5,875,168 shares of Common Stock for $16.625 per share in a public offering registered under the Securities Act of 1933, as amended

(the “Securities Act”). On March 24, 2006, the Power Fund sold 5,875,168 shares of Common Stock for $16.625 per share in a public offering registered under the Securities Act.

Item 6.

Contracts, Arrangements, Understandings or Relationships with Respect to Securities of the Issuer

Item 6 is hereby supplemented as follows:

Pursuant to the Registration Rights Agreement, dated as of April 20, 2004, as amended, by and among the OCM Funds, the Issuer and certain other stockholders of the Issuer, the Issuer will pay all expenses of the OCM Funds, other than underwriting discounts and commissions, in connection with the public offering referred to in Item 5(c) above, except for approximately $260,000 in offering expenses that the OCM Funds have agreed to reimburse to the Issuer.

On March 20, 2006, the OCM Funds entered into an Underwriting Agreement with Lehman Brothers Inc., Credit Suisse Securities (USA) LLC, Merrill, Lynch, Pierce, Fenner & Smith Incorporated and First Albany Capital Inc. (collectively, the “Underwriters”), the other selling stockholders named therein (together with the OCM Funds, the “Selling Stockholders”) and the Issuer for the sale by the Selling Stockholders of an aggregate of 13,000,000 shares of Common Stock and, at the election of the Underwriters, up to 1,950,000 additional shares to cover over-allotments. See the Form of Underwriting Agreement, which is incorporated herein by reference to Exhibit 1.1 to the Registration Statement, as provided in Item 7 herein.

Item 7.

Material to Be Filed as Exhibits

Exhibit 1

Form of Underwriting Agreement (incorporated by reference to Exhibit 1.1 to the Registration Statement on Form S-3 (File No. 333-132112), as filed by the Issuer on March 1, 2006, as amended).

Exhibit 2

A written agreement relating to the filing of the joint acquisition statement as required by Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended.

/s/ Christopher Brothers

Name:

Christopher Brothers

Title:

Managing Director

/s/ Lisa Arakaki

Name:

Lisa Arakaki

Title:

Senior Vice President, Legal

/s/ Ian Schapiro

Name:

Ian Schapiro

Title:

Principal

OCM PRINCIPAL OPPORTUNITIES FUND II, L.P.

By:

Oaktree Capital Management, LLC,

its general partner

/s/ Christopher Brothers

Name:

Christopher Brothers

Title:

Managing Director

/s/ Lisa Arakaki

Name:

Lisa Arakaki

Title:

Senior Vice President, Legal

OCM/GFI POWER OPPORTUNITIES FUND, L.P.

By:

Oaktree Capital Management, LLC,

its co-general partner

/s/ Christopher Brothers

Name:

Christopher Brothers

Title:

Managing Director

/s/ Lisa Arakaki

Name:

Lisa Arakaki

Title:

Senior Vice President, Legal

Exhibit 1

Form of Underwriting Agreement (incorporated by reference to Exhibit 1.1 to the Registration Statement on Form S-3 (File No. 333-132112), as filed by the Issuer on March 1, 2006, as amended).

Exhibit 2

A written agreement relating to the filing of the joint acquisition statement as required by Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended.